Package org.thymeleaf.context

Class LazyContextVariable<T>

Object

org.thymeleaf.context.LazyContextVariable<T>

Type Parameters:

T - the type of the value being returned by this variable

All Implemented Interfaces:

ILazyContextVariable<T>

public abstract class LazyContextVariable<T>
extends Object
implements ILazyContextVariable<T>

Basic abstract implementation for the ILazyContextVariable interface.

By extending this class instead of directly implementing the ILazyContextVariable interface, users can make sure that their variables will be initialized only once (per template execution). Once its inner abstract loadValue() method is called --which implementation has to be provided by the user--, objects of this class will cache the results of such load and return these results every time the variable value is accessed.

An example:

 context.setVariable(
     "users",
     new LazyContextVariable<List<User>>() {
         @Override
         protected List<User> loadValue() {
             return databaseRepository.findAllUsers();
         }
     });
 

Since:

3.0.0

Author:

Daniel Fernández

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	LazyContextVariable()

Method Summary

Modifier and Type	Method	Description
T	getValue()	Lazily resolve the value.
protected abstract T	loadValue()	Perform the actual resolution of the variable's value.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

LazyContextVariable

protected LazyContextVariable()

Method Detail

getValue

public final T getValue()

Lazily resolve the value.

This will be transparently called by the Thymeleaf engine at template rendering time when an object of this class is resolved in a Thymeleaf expression.

Note lazy variables will be resolved just once, and their resolved values will be reused as many times as they appear in the template.

Specified by:

getValue in interface ILazyContextVariable<T>

Returns:

the resolved value.

loadValue

protected abstract T loadValue()

Perform the actual resolution of the variable's value.

This method will be called only once, the first time this variable is resolved.

Returns:

the resolved value.